New York City Climate Evolution

Using data from Nasa Gisstemp, I have made a study about the evolution of the temperature at the Central Park Weather Station located in the heart of the city of New York. This station is particularly interesting because its data started to be measured in 1880 and it has only a few months with missed information (39 months among 1608 others). Therefore, it is quite possible to make an appropriate assessment over it.

The great conclusion is that it is very easy to observe a warming trend in the entire series of the Central Park Weather Station. 

The chart above clearly shows this trend, but differently of what is pointed by the common sense, this up trend has begun in the begining of the series, and not only in the current "global warming period". As we can see the city has passed through a flat trend in the middle of the last century (between the 50's and the 80's), though it's started a new uptrend after that. Some have called this recent uptrend as the so called "global warming".

The year of 2014 finished as a normal year in New York with no deviation to the average seen in the 1931/1960 period, and just a little bit warmer than the 1961/1990 period. However, when isolated, this data does not mean too much. The last chart has just explained that. It is quite clear that the current moment lived by new yorkers is the warmest in more than a century of collected data.

If we summarize the data in a spreadsheet, it is possible to verify this tendency with more details.

It is possible to notice the stabilization of the annual average temperature in the sencond half of the 20th century untill late 80's. Since then this number increased around 1C in nearly 25 years, the same rate experienced between the last fifth of the 19th century and the 40's.

Winter (DJF) and spring (MAM), both have been the main seasons to push up this warming trend, highlighting the role played by february, april and december. Below it is presented two charts illustrating this.

The winter average temperature is now 2,1C in the almost finished period of 30 years (1991/2014). It used to be just 0,2C in the 1901/1930 period and -0,1C in the 1881/1910 period. That is really remarkable.

Spring has not registered as much warming up as winter, but it is still shifting a lot and its line drawn by the chart shows a more constant warming trend.

Summer (JJA) and particularly autumn (SON) have been more stable.

Regarding the behaviour of some particular months, it is seen that october, january and september, especially the last one, they contrast with all others. October and january are showing no warming, and september has even cooled down through the entire series.

Nowadays New York City has almost made a swap of some of its month average temperatures because of its local warming. It is the example given by february and march, or by december and november. The average temperature that december and march used to register in the 1881/1890 decade is now almost the average temperature measured in november and february, respectively. Curious, isn't it?

Below we have a picture of the New York Central Park Weather Station for those who have never been to the site. I took this picture in 2009.